Neutrons open a window and examine space glass

Thanks to human ingenuity and zero gravity, we are reaping important benefits from science in space. Consider smartphones with built-in navigation systems and cameras.

Such transformative technologies seem to fit into the rhythm of our daily lives overnight. But they arose from years of discovery and development of materials that can withstand the harsh environment outside of our atmosphere. They develop from decades of laying the groundwork in basic science to understand how atoms behave in different materials under different conditions.

Building on this past, a global team of researchers has set a new benchmark for future experiments to produce materials in space rather than space. The team included members from the Department of Energy’s Oak Ridge and Argonne National Laboratories, Materials Development, Inc., NASA, the Japan Aerospace Exploration Agency or JAXA, the ISIS Neutron and Muon Source, Alfred University, and the University of New Mexico. Together, they found that many types of glass, including those that could be developed for next-generation optical devices, have a similar atomic structure and arrangement and can be successfully produced in space.

The team’s work is published in a journal npj Microgravity.

“The goal is to get a feel for the mechanisms behind space manufacturing that can lead to materials that aren’t necessarily available on Earth,” said Jörg Neuefeind, who joined ORNL in 2004 to build an instrument called NOMAD at the Spallation Neutron Source Laboratory. (SNS). NOMAD, the world’s fastest neutron diffractometer, helps scientists measure the arrangement of atoms by seeing how neutrons bounce off them. NOMAD is one of 20 instruments at the CIS that help scientists answer big questions and spur countless innovations, such as drugs that treat disease more effectively, more reliable airplane and rocket engines, cars with better gas mileage, and batteries that are safer to charge faster and last longer. .

JAXA operators on Earth manufactured and melted glass aboard the International Space Station (ISS) by remote control using a levitator. Levitators are used to suspend material samples during experiments to prevent interference from contact with other materials.

Once the next ISS mission ended months later and the space glass was brought back to Earth, researchers used a combination of techniques that included neutrons, X-rays and powerful microscopes to measure and compare the glass made and melted in the heavens and on Earth.

“We found that using containerless techniques like the levitator, we can create unconventional glasses in microgravity,” said JAXA’s Takehiko Ishikawa, who pioneered the electrostatic levitator used to make the glass beads aboard the ISS.

The researchers relied on NOMAD from the SNS to study the glass samples with neutrons and beams at Argonne’s Advanced Photon Source to study the samples with X-rays. Both SNS and APS are DOE Office of Science user facilities.

“There’s only so much material you can fly into space and back, and that was actually one of the reasons why NOMAD was so well suited for this experiment,” said Stephen Wilke of Materials Development Inc. and Argonne Visiting Scientist. . “We were only returning individual glass spheres about eight inches in diameter, which are very difficult to measure in terms of atomic structure. Because NOMAD excels at measuring extremely small samples, it allowed us to easily compare the individual spheres we made in the lab with those made on the space station.”

Mysteries of glass

The glass, it turns out, is not so clean. Unlike crystalline solids such as salt, glass atoms do not have a uniform structure. Its unusual atomic arrangement, while remarkably stable, is perhaps best described as a random network of molecules that share coordination atoms. Glass is neither completely solid nor completely liquid, but also comes in a variety of forms, including polymer, oxide, and metal, such as eyeglass lenses, fiber optic fibers, and hardware for deep space missions.

In 2022 Neuefeind, Wilke and Rick Weber, glass experts, experimented with two oxides of neodymium and titanium and discovered potential for optical applications. The combination of these two elements shows unusual strengths that have not been seen in similar research campaigns. These findings led them to continue their current studies with NASA.

“[The experiment in 2022] taught us something really remarkable,” said Materials Development Inc.’s Weber. These glasses have a grid of six coordinates. They really are out there. It’s exciting from a glass science perspective. But from a practical point of view, it also means more opportunities for new things with optical materials and new kinds of devices.”

Scientists often use neutrons and X-rays in parallel to collect data that no other techniques can produce, allowing us to understand the arrangement of atoms of various elements in a sample. Neutrons helped the team see lighter elements in space glass, like oxygen, while X-rays helped them see heavier elements like neodymium and titanium. If there were significant differences between space glass and terrestrial glass, they would likely be in the oxide sublattice or arrangement of oxygen atoms, the distribution of heavy atoms, or both.

Neutrons will become increasingly important tools for unlocking the mysteries of matter as scientists explore new frontiers, regardless of space.

“We need to understand not only the effects of space on matter, but also its effects on how things form,” Neuefeind said. “Because of their unique properties, neutrons are part of the solution to this kind of puzzle.”